Arch said:I wonder if they used to work better than they do now - these days there are a lot more distractions and background clutter in the average urban setting - advertising signs, street furniture, the sheer number of car lights. In a darker, simpler setting (a rural or suburban road), a little strip of reflective would probably stand out more.
Clean light conditions often do work very well with retro reflectives.
Your idea about urban clutter is an interesting one. I'd have thought it probably varies from driver to driver.